Theoretical Population Biology最新文献_第2页

Dynamics of the distribution of fitness effects during adaptation 适应度效应在适应过程中的动态分布。

IF 1.3 4区生物学 Q4 ECOLOGY

Theoretical Population Biology

Pub Date : 2025-12-01 Epub Date: 2025-09-22 DOI: 10.1016/j.tpb.2025.09.003

Tenoch Morales, Abigail Kushnir, Lindi M. Wahl

Empirical measures of the distribution of fitness effects of new mutations (the DFE) have been increasingly successful, and have recently highlighted the fact that the DFE changes during adaptation. Here, we analyze these dynamic changes to the DFE during a simplified adaptive process: an adaptive walk across an additive fitness landscape. First, we derive analytical approximations for the underlying fitness distributions of alleles present in the genotype and available through mutation and use these to derive expressions for the DFE at each step of the adaptive walk. We then confirm these predictions with independent simulations that relax several simplifying assumptions made in the analysis. As expected, our analysis predicts that as adaptation proceeds, the DFE is reshaped dynamically throughout the walk by a decrease in the beneficial fraction of mutations (a shift to the left). Surprisingly, different mechanisms drive this change depending on the number of alleles available per site: for a small number of available alleles, we observe a depletion of high-fitness alleles available through mutation as expected, however for a large number of alleles we observe that adaptation may be more limited by the availability of low-fitness alleles to be replaced, rather than by the availability of high-fitness alleles to replace them.

新突变适应度效应分布（DFE）的实证测量越来越成功，最近强调了DFE在适应过程中发生变化的事实。在这里，我们分析了在一个简化的适应过程中DFE的这些动态变化：在一个附加适应度景观上的自适应行走。首先，我们推导出基因型中存在的等位基因的潜在适应度分布的分析近似，并通过突变获得，并使用这些近似来推导出适应行走每一步的DFE的表达。然后，我们用独立的模拟来证实这些预测，这些模拟放松了分析中做出的几个简化假设。正如预期的那样，我们的分析预测，随着适应的进行，DFE在整个行走过程中通过有益突变比例的减少（向左移动）动态重塑。令人惊讶的是，不同的机制驱动这种变化取决于每个位点可用的等位基因的数量：对于少数可用的等位基因，我们观察到预期的高适应度等位基因通过突变耗尽，然而对于大量的等位基因，我们观察到适应可能更多地受到低适应度等位基因替代的可用性的限制，而不是高适应度等位基因替代它们的可用性。

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引用次数: 0

The asymmetry between spite and altruism 怨恨和利他之间的不对称。

IF 1.3 4区生物学 Q4 ECOLOGY

Theoretical Population Biology

Pub Date : 2025-12-01 Epub Date: 2025-11-19 DOI: 10.1016/j.tpb.2025.11.001

Shun Kurokawa , Sabin Lessard

Empirical evidence suggests that altruistic social behavior (helping others at a cost to oneself) is more common than spiteful behavior (harming others at a cost to oneself) in nature. Here, we provide a general mathematical explanation for this asymmetry based on fundamental constraints on the composition of social groups. Since both behaviors are costly to the actor, they require additional mechanisms to avoid being eliminated by natural selection, such as assortative interactions. When interactions tend to occur between similar individuals (positive assortment), altruism can evolve, whereas spite requires negative assortment. We use a linear game in groups of fixed size n to derive an index of assortativity, and we analyze evolution in both infinite and finite populations. We show that positive assortment faces no fundamental limits – complete segregation into homogeneous groups is always mathematically possible. In contrast, negative assortment is constrained, especially in larger groups and unbalanced populations. This asymmetry creates more opportunities for altruism to evolve than spite. Our results explain the empirical rarity of spiteful behavior without assuming any specific population structure or group formation mechanism, suggesting that the scarcity of spite may reflect fundamental mathematical constraints inherent to assortment patterns.

经验证据表明，在本质上，利他主义的社会行为（以牺牲自己为代价帮助他人）比恶意行为（以牺牲自己为代价伤害他人）更为常见。在这里，我们基于社会群体构成的基本约束，对这种不对称提供了一般的数学解释。由于这两种行为对行动者来说都是昂贵的，它们需要额外的机制来避免被自然选择淘汰，比如分类互动。当相互作用倾向于发生在相似的个体之间（积极分类）时，利他主义就会进化，而怨恨则需要消极分类。我们在固定规模n的群体中使用线性博弈来推导出分类指数，并分析了无限和有限群体中的进化。我们表明，正分类没有根本的限制——完全分离成同质群体在数学上总是可能的。相反，负分类受到限制，特别是在较大的群体和不平衡的群体中。这种不对称为利他主义的进化创造了比怨恨更多的机会。我们的研究结果解释了恶意行为的经验稀缺性，而没有假设任何特定的群体结构或群体形成机制，这表明恶意行为的稀缺性可能反映了分类模式固有的基本数学约束。

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引用次数: 0

Computing tree size under dynamical models of diversification 动态多样化模型下的树大小计算。

IF 1.3 4区生物学 Q4 ECOLOGY

Theoretical Population Biology

Pub Date : 2025-12-01 Epub Date: 2025-10-27 DOI: 10.1016/j.tpb.2025.10.003

Ailene MacPherson , Matt Pennell

A phylogenetic tree has three types of attributes: size, shape (topology), and branch density. Phylodynamic studies are often motivated by questions regarding the size of clades, nevertheless, nearly all of the inference methods only make use of the other two attributes. In this paper, we ask whether there is additional information if we consider tree size more explicitly in phylodynamic inference methods. To address this question, we first needed to be able to compute the expected tree size distribution under a specified phylodynamic model; perhaps surprisingly, there is not a general method for doing so — it is known what this is under a Yule or constant rate birth–death model but not for the more complicated scenarios researchers are often interested in. We present three different solutions to this problem: using (i) the deterministic limit; (ii) master equations; and (iii) an ensemble moment approximation. Using simulations, we evaluate the accuracy of these three approaches under a variety of scenarios and alternative measures of tree size (i.e., sampling through time or only at the present; sampling ancestors or not). We then use the most accurate measures for the situation, to investigate the added informational content of tree size. We find that for two critical phylodynamic questions — (i) is diversification diversity dependent? and, (ii) can we distinguish between alternative diversification scenarios? — knowing the expected tree size distribution under the specified scenario provides insights that could not be gleaned from considering the expected shape and branch density alone. The contribution of this paper is both a novel set of methods for computing tree size distributions and a path forward for richer phylodynamic inference into the evolutionary and epidemiological processes that shape lineage trees.

系统发育树有三种类型的属性：大小、形状（拓扑结构）和分支密度。系统动力学研究经常被有关枝的大小的问题所激发，然而，几乎所有的推理方法都只利用了其他两个属性。在本文中，我们问是否有额外的信息，如果我们考虑树的大小更明确地在系统动力学推理方法。为了解决这个问题，我们首先需要能够在特定的系统动力学模型下计算预期的树大小分布；也许令人惊讶的是，没有一个通用的方法来做到这一点——在Yule或恒定速率的出生-死亡模型下，这是已知的，但对于研究人员经常感兴趣的更复杂的情况，这是未知的。我们对这个问题提出了三种不同的解决方案：使用(i)确定性极限；（ii）主方程；和（iii）一个集合矩近似。通过模拟，我们评估了这三种方法在各种场景和树大小的替代测量下的准确性（即，随时间采样或仅在当前采样；采样祖先与否）。然后，我们使用最准确的测量方法来调查树大小的附加信息内容。我们发现，对于两个关键的系统动力学问题——(i)多样化是否依赖于多样性？（ii）我们能否区分不同的多样化方案？-了解在特定情况下预期的树木大小分布，可以提供仅考虑预期形状和树枝密度无法获得的见解。本文的贡献在于提供了一套计算树大小分布的新方法，并为形成谱系树的进化和流行病学过程提供了更丰富的系统动力学推断。

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引用次数: 0

Inconsistency of parsimony under the multispecies coalescent 多种合并下节俭的不一致性。

IF 1.3 4区生物学 Q4 ECOLOGY

Theoretical Population Biology

Pub Date : 2025-12-01 Epub Date: 2025-09-27 DOI: 10.1016/j.tpb.2025.09.004

Daniel A. Rickert , Louis Wai-Tong Fan , Matthew W. Hahn

While it is known that parsimony can be statistically inconsistent under certain models of evolution due to high levels of homoplasy, the consistency of parsimony under the multispecies coalescent (MSC) is less well studied. Previous studies have shown the consistency of concatenated parsimony (parsimony applied to concatenated alignments) under the MSC for the rooted 4-taxa case under an infinite-sites model of mutation; on the other hand, other work has also established the inconsistency of concatenated parsimony for the unrooted 6-taxa case. These seemingly contradictory results suggest that concatenated parsimony may fail to be consistent for trees with more than 5 taxa, for all unrooted trees, or for some combination of the two. Here, we present a technique for computing the expected internal branch lengths of gene trees under the MSC. This technique allows us to determine the regions of the parameter space of the species tree under which concatenated parsimony fails for different numbers of taxa, for rooted or unrooted trees. We use our new approach to demonstrate that while parsimony succeeds in the unrooted 5-taxa case, there are regions of statistical inconsistency for concatenated parsimony for rooted 5+-taxa cases and unrooted 6+-taxa cases. Our results therefore suggest that parsimony is not generally dependable under the MSC.

虽然我们知道，在某些进化模式下，由于高水平的同源性，简约性可能在统计上不一致，但对多物种聚结（MSC）下简约性的一致性研究较少。先前的研究表明，在无限位点突变模型下，MSC下的4个根分类群的串联简约性（应用于串联比对的简约性）的一致性；另一方面，其他研究也证实了6个分类群无根情况下串联简约性的不一致性。这些看似矛盾的结果表明，串联简约可能不符合5个以上分类群的树木、所有无根树木或两者的某些组合。在这里，我们提出了一种计算MSC下基因树的预期内部分支长度的技术。这种技术使我们能够确定物种树的参数空间的区域，在该区域内，对于不同数量的分类群，对于有根或无根的树，串联简约性失败。我们使用我们的新方法来证明，虽然在无根的5-分类群情况下简约性成功，但在有根的5+-分类群情况下和无根的6+-分类群情况下，串联简约性存在统计不一致的区域。因此，我们的结果表明，在MSC下，节俭通常是不可靠的。

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引用次数: 0

Tikhonov–Fenichel reductions and their application to a novel modelling approach for mutualism Tikhonov-Fenichel约简及其在互惠共生新建模方法中的应用。

IF 1.3 4区生物学 Q4 ECOLOGY

Theoretical Population Biology

Pub Date : 2025-12-01 Epub Date: 2025-09-11 DOI: 10.1016/j.tpb.2025.08.004

Johannes Apelt, Volkmar Liebscher

When formulating a model there is a trade-off between model complexity and (biological) realism. In the present paper we demonstrate how model reduction from a precise mechanistic “super model” to simpler conceptual models using Tikhonov–Fenichel reductions, an algebraic approach to singular perturbation theory, can mitigate this problem. Compared to traditional methods for time scale separations (Tikhonov’s theorem, quasi-steady state assumption), Tikhonov–Fenichel reductions have the advantage that we can compute a reduction directly for a separation of rates into slow and fast ones instead of a separation of components of the system. Moreover, we can find all such reductions algorithmically.

In this work we use Tikhonov–Fenichel reductions to analyse a mutualism model tailored towards lichens with an explicit description of the interaction. We find: (1) the implicit description of the interaction given in the reductions by interaction terms (functional responses) varies depending on the scenario, (2) there is a tendency for the mycobiont, an obligate mutualist, to always benefit from the interaction while it can be detrimental for the photobiont, a facultative mutualist, depending on the parameters, (3) our model is capable of describing the shift from mutualism to parasitism, (4) via numerical analyis, that our model experiences bistability with multiple stable fixed points in the interior of the first orthant. To analyse the reductions we formalize and discuss a mathematical criterion that categorizes two-species interactions. Throughout the paper we focus on the relation between the mathematics behind Tikhonov–Fenichel reductions and their biological interpretation.

在制定模型时，需要在模型复杂性和（生物）现实性之间进行权衡。在本文中，我们展示了如何使用奇异微扰理论的代数方法Tikhonov-Fenichel约简，从一个精确的机械“超级模型”到更简单的概念模型，可以缓解这个问题。与传统的时间尺度分离方法（Tikhonov定理，准稳态假设）相比，Tikhonov- fenichel约简的优点是，我们可以直接计算速率分离为慢速和快速的约简，而不是系统组件的分离。此外，我们可以通过算法找到所有这些约简。在本文中，我们使用Tikhonov-Fenichel约简来分析一个针对地衣的互惠模式，并明确描述了这种相互作用。我们发现:(1)通过相互作用项（功能响应）在减少中给出的相互作用的隐式描述因情景而异；(2)根据参数，真菌生物（义务互惠者）总是从相互作用中受益，而光生物（兼性互惠者）则可能有害；(3)我们的模型能够描述从互惠到寄生的转变；(4)通过数值分析。我们的模型具有双稳定性，在第一正交内具有多个稳定不动点。为了分析约简，我们形式化并讨论了对两种相互作用进行分类的数学标准。在整个论文中，我们关注的是吉洪诺夫-菲尼切尔约化背后的数学与它们的生物学解释之间的关系。

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引用次数: 0

A decomposition of a phylogenetically-informed distance between species assemblages into basal and terminal components 将物种组合之间的系统发育信息距离分解为基部和末端组分。

IF 1.3 4区生物学 Q4 ECOLOGY

Theoretical Population Biology

Pub Date : 2025-12-01 Epub Date: 2025-11-06 DOI: 10.1016/j.tpb.2025.10.002

Julia Fukuyama

Ecologists seeking to quantify differences between species assemblages often rely on dissimilarity measures that incorporate both species composition and the phylogenetic relatedness among species. Although many variants of such distances are available, their statistical properties remain poorly understood. For instance, an analyst comparing species abundances in two types of sites might apply PERMANOVA with UniFrac as the dissimilarity measure and obtain one result, but using PERMANOVA with Rao’s dissimilarity coefficient could yield a different conclusion. In other contexts, the pattern of significance might be reversed. While such discrepancies are well documented empirically, the mathematical underpinnings of this phenomenon are not well understood. We analyze a phylogenetically-informed distance that has been described many times in the literature under different names. Specifically, it corresponds to Rao’s DISC (Radhakrishna, 1982) with a certain choice of distance between species, has also been referred to as

H

(Jérôme et al., 2007),

δ^{C O}

(Sandrine et al., 2004), and is related to

P_{S T}

(Olivier and Bruno, 2007). We show that we can decompose this distance into pieces that describe basal and terminal phylogenetic structure and show that it places an overwhelming amount of weight on the basal phylogenetic structure. We show that a related class of distances used in other contexts can be interpreted as modulating the influence of the basal structure, demonstrate how this modification can increase power for detecting phylogenetically-structured effects at different scales, and present examples using both simulated and real datasets.

生态学家试图量化物种组合之间的差异，通常依赖于包括物种组成和物种之间系统发育亲缘关系的不相似性测量。虽然这种距离有许多变体，但它们的统计性质仍然知之甚少。例如，分析人员比较两种类型站点的物种丰度时，可能使用PERMANOVA和UniFrac作为不相似度度量并得到一个结果，但使用PERMANOVA和Rao的不相似系数可能会得到不同的结论。在其他情况下，重要性的模式可能相反。虽然这种差异在经验上有很好的记录，但这种现象的数学基础还没有得到很好的理解。我们分析了一个在系统发育上被告知的距离，这个距离在文献中以不同的名字被描述了很多次。具体来说，它对应于Rao的DISC (Radhakrishna, 1982)，具有一定的种间距离选择，也被称为H (Jérôme et al., 2007), δCO (Sandrine et al., 2004)，与PST （Olivier and Bruno, 2007）有关。我们表明，我们可以将这个距离分解成描述基础和终端系统发育结构的片段，并表明它对基础系统发育结构具有压倒性的重要性。我们展示了在其他情况下使用的相关距离类别可以被解释为调节基础结构的影响，展示了这种修改如何增加在不同尺度上检测系统发育结构效应的能力，并使用模拟和真实数据集提供了示例。

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引用次数: 0

Using mathematical constraints to explain narrow ranges for allele-sharing dissimilarities 利用数学约束解释等位基因共享差异的狭窄范围。

IF 1.3 4区生物学 Q4 ECOLOGY

Theoretical Population Biology

Pub Date : 2025-12-01 Epub Date: 2025-06-17 DOI: 10.1016/j.tpb.2025.05.002

Xiran Liu , Zarif Ahsan , Noah A. Rosenberg

Allele-sharing dissimilarity (ASD) statistics are measures of genetic differentiation for pairs of individuals or populations. Given the allele-frequency distributions of two populations — possibly the same population — the expected value of an ASD statistic is computed by evaluating the expectation of the pairwise dissimilarity between two individuals drawn at random, each from its associated allele-frequency distribution. For each of two ASD statistics, which we term

D_{1}

and

D_{2}

, we investigate the extent to which the expected ASD is constrained by allele frequencies in the two populations; in other words, how is the magnitude of the measure bounded as a function of the frequency of the most frequent allelic type? We first consider dissimilarity of a population with itself, obtaining bounds on expected ASD in terms of the frequency of the most frequent allelic type in the population. We then examine pairs of populations that might or might not possess the same most frequent allelic type. Across the unit interval for the frequency of the most frequent allelic type, the expected allele-sharing dissimilarity has a range that is more restricted than the

[0, 1]

interval. The mathematical constraints on expected ASD assist in explaining a pattern observed empirically in human populations, namely that when averaging across loci, allele-sharing dissimilarities between pairs of individuals often tend to vary only within a relatively narrow range.

等位基因共享差异（ASD）统计是对个体或群体的遗传分化的测量。给定两个群体的等位基因频率分布——可能是同一个群体——ASD统计的期望值是通过评估随机抽取的两个个体之间的两两差异的期望值来计算的，每个个体都来自其相关的等位基因频率分布。对于我们称之为D1和D2的两个ASD统计数据中的每一个，我们研究了预期的ASD在多大程度上受到两个人群中等位基因频率的限制；换句话说，测量的大小是如何作为最常见的等位基因类型频率的函数限定的？我们首先考虑群体与自身的不相似性，根据群体中最常见的等位基因类型的频率获得预期ASD的界限。然后，我们检查可能或可能不具有相同的最常见的等位基因类型的成对群体。在最常见的等位基因类型频率的单位区间内，预期的等位基因共享不相似性的范围比[0,1]区间更受限制。对预期自闭症谱系障碍的数学限制有助于解释在人类群体中观察到的一种模式，即当对基因座进行平均时，成对个体之间的等位基因共享差异往往只在一个相对狭窄的范围内变化。

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引用次数: 0

The distribution of the number of mutations in the genealogy of a sample from a single population 突变数：来自单一种群的一个样本的家谱中突变数的分布

IF 1.3 4区生物学 Q4 ECOLOGY

Theoretical Population Biology

Pub Date : 2025-10-01 Epub Date: 2025-08-26 DOI: 10.1016/j.tpb.2025.08.001

Yun-Xin Fu

The number

K

of mutations in the genealogy of a sample of

n

sequences from a single population is one essential summary statistic in molecular population genetics and is equal to the number of segregating sites in the sample under the infinite-sites model. Although its expectation and variance are the most widely utilized properties, its sampling formula (i.e., probability distribution) is the foundation for all explorations related to K. Despite existence of an analytic sampling formula, its numerical application is limited due to susceptibility to error propagation. This paper presents a new sampling formula for

K

in a random sample of DNA sequences from a neutral locus without recombination, taken from a single population evolving according to the Wright–Fisher model with a constant effective population size, or the constant-in-state model, which allows the effective population size to vary across different coalescent states. The new sampling formula is expressed as the sum of the probabilities of the various ways mutations can manifest in the sample genealogy and achieves simplicity by partitioning mutations into hypothetical atomic clusters that cannot be further divided. Under the Wright–Fisher model with a constant effective population size, the new sampling formula is closely analogous to the celebrated Ewens’ sampling formula for the number of distinct alleles in a sample. Numerical computation using the new sampling formula is accurate and is limited only by the burden of enumerating a large number of partitions of a large K. However, significant improvement in efficiency can be achieved by prioritizing the enumeration of partitions with a large number of parts.

在分子群体遗传学中，单个群体的n个序列样本的家谱突变数K是一个重要的汇总统计量，在无限位点模型下等于样本中的分离位点数。虽然它的期望和方差是最广泛使用的性质，但它的抽样公式（即概率分布）是所有与k相关的探索的基础。尽管存在解析抽样公式，但由于易受误差传播的影响，其数值应用受到限制。根据Wright-Fisher模型（有效群体规模恒定）或恒态模型（允许有效群体规模在不同的聚合状态下变化），从一个无重组的中性位点DNA序列的随机样本中，提出了一个新的K抽样公式。新的抽样公式表示为突变在样本谱系中表现的各种方式的概率之和，并通过将突变划分为不能进一步划分的假想原子簇来实现简单性。在有效群体大小不变的Wright-Fisher模型下，新的抽样公式与著名的evens样本中不同等位基因数量的抽样公式非常相似。使用新抽样公式的数值计算是准确的，并且仅受枚举大k的大量分区的负担的限制。然而，通过优先枚举具有大量零件的分区可以显着提高效率。

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引用次数: 0

Prevalence of social parasitism in ant populations: Modeling energetics, demography and space in the Polyergus/Formica system 蚁群中社会寄生性的流行：Polyergus/Formica系统的能量学、人口学和空间建模。

IF 1.3 4区生物学 Q4 ECOLOGY

Theoretical Population Biology

Pub Date : 2025-10-01 Epub Date: 2025-08-11 DOI: 10.1016/j.tpb.2025.08.002

Patrick J. Talley , Frederick R. Adler

Obligatory interspecific brood raiding is a unique form of parasitism in which one ant species steals pupae from another species and raises them into workers to perform duties within its nest. Although this strategy can support very large colonies, the relative species abundance of these social parasites is always low. Using fully parameterized mathematical models of the growth and reproduction of the well-studied interaction between brood raider Polyergus and its hosts in the genus Formica, we aim to discover the mechanisms that limit brood raider abundance. These mathematical models explain the range of observed relative species abundance of these social parasites and provide a criterion for Polyergus persistence within a patch of hosts. In particular, Polyergus colony survival depends on the number of host colonies between 23 and 73 meters from their nest—close enough to raid but distant enough to survive raiding. The number sets the upper bound of Polyergus abundance to be less than 10% of the community. Furthermore, we quantify the fitness costs imposed by brood raiding on nearby host colonies, which can be effectively castrated by the constant drain on their worker resources. These findings provide a mechanistic framework for understanding the ecological constraints on social parasitism, its role in shaping ant community dynamics and its connection to the evolution of host defense strategies.

强制性的种间寄生是一种独特的寄生形式，一种蚂蚁从另一种蚂蚁那里窃取蛹，并将它们培养成工蚁，在巢中履行职责。虽然这种策略可以支持非常大的群体，但这些群居寄生虫的相对物种丰度总是很低。利用已被充分研究的胶木属掠巢虫与寄主之间相互作用的全参数化数学模型，我们旨在发现限制掠巢虫丰度的机制。这些数学模型解释了观察到的这些群居寄生虫相对物种丰度的范围，并为聚螨在一个寄主斑块内的持久性提供了一个标准。特别是，波利格斯蚁群的生存取决于距离它们巢穴23米到73米之间的寄主蚁群的数量——近到足以发动袭击，但远到足以在袭击中幸存。这一数字表明，水蛭丰度的上限小于群落的10%。此外，我们还量化了蜂群突袭对附近寄主群体造成的适应性成本，这些寄主群体可以通过不断消耗工蜂资源而有效地阉割。这些发现为理解社会寄生的生态限制、其在塑造蚂蚁群落动态中的作用及其与宿主防御策略进化的联系提供了一个机制框架。

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引用次数: 0

Identity-by-descent segments in large samples 大样本中的血统识别片段。

IF 1.2 4区生物学 Q4 ECOLOGY

Theoretical Population Biology

Pub Date : 2025-10-01 Epub Date: 2025-07-05 DOI: 10.1016/j.tpb.2025.06.003

Seth D. Temple , Elizabeth A. Thompson

If two haplotypes share the same alleles for an extended gene tract, these haplotypes are likely to be derived identical-by-descent from a recent common ancestor. Identity-by-descent segment lengths are correlated via unobserved ancestral tree and recombination processes, which commonly presents challenges to the derivation of theoretical results in population genetics. We show that the proportion of detectable identity-by-descent segments around a locus is normally distributed when the sample size and the scaled population size are large. We generalize this central limit theorem to cover flexible demographic scenarios, multi-way identity-by-descent segments, and multivariate identity-by-descent rates. The regularity conditions on sample size and scaled population size are unlikely to hold in genetic data from real populations, but provide intuition for when the Gaussian distribution may be a reasonable approximate model for the IBD rate. We use efficient simulations to study the distributional behavior of the detectable identity-by-descent rate. One consequence of non-normality in finite samples is that a genome-wide scan looking for excess identity-by-descent rates may be subject to anti-conservative control of family-wise error rates.

如果两个单倍型在一个扩展的基因束中具有相同的等位基因，那么这些单倍型很可能是由最近的共同祖先遗传而来的。血统身份片段长度通过未观察到的祖先树和重组过程相关联，这通常对群体遗传学理论结果的推导提出了挑战。我们表明，当样本大小和尺度总体大小较大时，基因座周围可检测的血统身份片段的比例呈正态分布。我们将这个中心极限定理推广到灵活的人口统计场景、多向血统分段和多变量血统率。样本大小和比例群体大小的规则条件不太可能在真实群体的遗传数据中成立，但为高斯分布何时可能是IBD率的合理近似模型提供了直觉。我们使用有效的模拟来研究可检测的下降身份率的分布行为。在有限样本中，非正态性的一个后果是，在全基因组扫描中寻找过多的血统识别率，可能会受到家庭误差率的反保守控制。

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引用次数: 0